Advice for first running of a .049 and .090
10-31-2012, 06:00 AM
#1
Advice for first running of a .049 and .090
Hi Gang,
Not sure if you were following my previous posts, but I'm fooling around with some old Ducted Fan stuff as a nestogic build. I have two NIB Tee Dee's. I have an .049 and .090. Both are mounted and ready to run. I need a little break in advice and set up guidance here if you guys could be so kind to ablidge. I have not run a 1/2 engine since I was in grade school. All I could find for fuel was 24% from glow plug boy on E-bay. Here are some questions I have:
What fuel should I use, and where can I get it?
Do I need special fuel for break in?
How many head gaskets should be on the motor?
I am starting with an electric starter, what needle valve settings should I start with (the .049 has the fine thread 128TPI conversion)?
What voltage is the glow plug, can I use my variable power panel from my glow stuff?
Much thanks in advance and I'll keep you posted!
Kind regards,
Rick
Not sure if you were following my previous posts, but I'm fooling around with some old Ducted Fan stuff as a nestogic build. I have two NIB Tee Dee's. I have an .049 and .090. Both are mounted and ready to run. I need a little break in advice and set up guidance here if you guys could be so kind to ablidge. I have not run a 1/2 engine since I was in grade school. All I could find for fuel was 24% from glow plug boy on E-bay. Here are some questions I have:
What fuel should I use, and where can I get it?
Do I need special fuel for break in?
How many head gaskets should be on the motor?
I am starting with an electric starter, what needle valve settings should I start with (the .049 has the fine thread 128TPI conversion)?
What voltage is the glow plug, can I use my variable power panel from my glow stuff?
Much thanks in advance and I'll keep you posted!
Kind regards,
Rick
10-31-2012, 08:15 AM
#3
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RE: Advice for first running of a .049 and .090
Good Afternoon,
In regards to fuel, you typically want a nitro content around 25% and to have an oil content of 20% (half of that should be castor oil). GPB fuel is usually a nice blend for Cox. I usually recommend Sig Champion 25% nitro. If you cannot find it locally, they sell it online by the pint, quart, and gallon.
On the TD there are typically 3 .005 annealed copper head gaskets installed from the factory. They give you 3 because starting is easier that way, especially for new engines. I would start the engine and run it rich for about 3/4 tanks of fuel. After that you can bring it up to peak RPM's and start playing with the removal of head gaskets until you are left with 1. Every engine is a little different, so it may run optimal with 2 or 3 gaskets.
Typical needle settings are 4 to 4 1/2 turns on a TD.
You want to run 1.5 volts to the glow plug and not more than that. While you may be able to get away with a little more voltage, it will decrease the longevity of the glow head.
Send me an email, [email protected] and I can send over a copy of the TD manual.
Best Regards, Matt
In regards to fuel, you typically want a nitro content around 25% and to have an oil content of 20% (half of that should be castor oil). GPB fuel is usually a nice blend for Cox. I usually recommend Sig Champion 25% nitro. If you cannot find it locally, they sell it online by the pint, quart, and gallon.
On the TD there are typically 3 .005 annealed copper head gaskets installed from the factory. They give you 3 because starting is easier that way, especially for new engines. I would start the engine and run it rich for about 3/4 tanks of fuel. After that you can bring it up to peak RPM's and start playing with the removal of head gaskets until you are left with 1. Every engine is a little different, so it may run optimal with 2 or 3 gaskets.
Typical needle settings are 4 to 4 1/2 turns on a TD.
You want to run 1.5 volts to the glow plug and not more than that. While you may be able to get away with a little more voltage, it will decrease the longevity of the glow head.
Send me an email, [email protected] and I can send over a copy of the TD manual.
Best Regards, Matt
10-31-2012, 10:55 AM
#4
Senior Member
RE: Advice for first running of a .049 and .090
Make sure you have a good hot battery. I think 90% of the problems starting Cox engines is due to a glow plug not hot enough. I use a 2 volt cyclon gelcell with a long lead, and like Cox plugs to light up like a flashlight, Well, at least bright orange. Cox plugs are generally very robust and you can get many, many runs off one. On the other hand, I have had a couple which burned out on first application of the battery.
You don't need a starter. Suck fuel up to the carb, prime in the exhaust with the piston up, turn the prop backwards to vertical. Attach the battery and hit the prop forward with your gloved finger. With a little practice this will work 99% of the time. I haven't run
a TD 049 in many years, but this worked fine when mouse racing. Incidentally, I run Cox TD 049 and larger engines on crankcase pressure off the backplate.
I've been flying a TD 09 a lot, Cox 7 x 3.5 prop and Sig Champion fuel 10% nitro, 20% oil, half synthetic, half castor. I used to run TD 09s on 25% nitro, but I think they are more reliable on needle setting on my present fuel. The TD 09 needle works fine with crankcase pressure. The 049 needs a fine thread needle from Texas Timers. I run a one way valve in the pressure line.
Run the engines a little rich for the first couple of tanks and they are ready to go.
You don't need a starter. Suck fuel up to the carb, prime in the exhaust with the piston up, turn the prop backwards to vertical. Attach the battery and hit the prop forward with your gloved finger. With a little practice this will work 99% of the time. I haven't run
a TD 049 in many years, but this worked fine when mouse racing. Incidentally, I run Cox TD 049 and larger engines on crankcase pressure off the backplate.
I've been flying a TD 09 a lot, Cox 7 x 3.5 prop and Sig Champion fuel 10% nitro, 20% oil, half synthetic, half castor. I used to run TD 09s on 25% nitro, but I think they are more reliable on needle setting on my present fuel. The TD 09 needle works fine with crankcase pressure. The 049 needs a fine thread needle from Texas Timers. I run a one way valve in the pressure line.
Run the engines a little rich for the first couple of tanks and they are ready to go.
11-01-2012, 08:43 AM
#6
RE: Advice for first running of a .049 and .090
Well, I used to work at Cox and here is what we did:
The time to re-set the piston/con rod is when the engine is new, BEFORE the crimped socket work hardens from running, so check it and do it now if it is loose.
Depending on the vintage and quality of the TDs you have, some of the older ones had a a very tight fitment of the piston and cylinder due to the tapers, while laters ones have a relatively sloppy fit and little or no taper. This then means that the tight ones will take over an hour or more of break in while the sloppy ones will be ready after as little as 5 minutes of running. If the piston gets real tight for the last 1/16 to 1/8 inch of travel, at the top of the stroke (glow head removed) it will need a longer break-in. In any case, here is how we broke them in at Cox prior to testing them for peak RPM:
Run the TD .049 on 15% fuel and use a smaller prop, like a 5x3. Keep the glow plug clip on and run it sloppy rich for the first couple tanks full ( about 5 minutes each time) and let it cool between runs. Check that the glow head is tight after it cools. You will notice some greyish-black metal in the oil during the first run, but it shoul go away by the second run. The idea is to keep the engine turning fast but rich, with a smaller prop.
Run several more tanks with the glow clip removed, you will have to slightly lean the needle valve to keep the engine running, but keep it on the rich side. Next, after cool down and torqing the glow head, run it a bit leaner such that it is on the verge of occasionally 2-cycling. The engine should be 4-cycling, but going back and forth between a 2-cycle and 4-cycle. This will begin to build a little heat in the engine. Repeat this 3-4 times for 5 minutes each and then with the engine running, pinch the fuel line to momentarily lean out the engine for full rpm for about 5 seconds, then release the fuel line and let it go rich for about 15 seconds, then repeat. If at anytime during this process the engine begins to sag while you are pinching the line, it's getting tight and is not ready for full RPM, or you just pinched the line too long and it's running out of fuel. If all is well, try leaning the needle valve a little more until it the engine is just barely missing a little and almost on a clean 2-cycle. It should be making a "whee....da-deee......da-deee..." sound. If the engine can hold this setting without sagging, try pinching the line again and see how it runs when lean. Run several more tanks and then try leaning it fully. If it sags, open the needle valve and continue the break in with it set so it just misses as described above.
Once the engine will hold a lean setting without sagging, you are ready to try the full size prop. Bolt on a 6x3 grey and start over with a rich run where its on the verge of breaking into a clean 2-cycle as described above. Pinch the line and note how it holds the lean setting. If it seems fine, try leaning out the needle valve fully on the next run. Loose engines will be ready at this point, but tight engines will require more rich running with a full load( the bigger prop) before they can hold a lean setting. Since no two are alike, you have listen to the engine to determine when it is ready. If the engine will not hold a lean setting and tightens up, go back to the 5x3 and continue break-in at a fast 4-cycle for another 15 minutes. On tighter engines, it is well worth the extra effort, as they will be real power houses once broke in, but if you rush it you will ruin them.
Many times, if the engine is tightening up repeatedly, it may have varnish/shellac in the cylinder and you will have to scour the cylinder wall with #0000 steel wool or a devarnishing brush ( rifle bore brushes work well). Clean the cylinder, lube, and re-assemble the engine and continue the break-in.
Do the same for the .09 TD. The secrets are using a small break-in prop to allow the engine to build RPM, while running rich to avoid a heat seizure, allowing the engine to fully cool between runs (heat cycling) and slowly bringing up the RPM incrementally as the break-in progresses. An extended break-in will not hurt an engine, but you can ruin a tight engine by not breaking it in long enough.
Have fun, good luck!
The time to re-set the piston/con rod is when the engine is new, BEFORE the crimped socket work hardens from running, so check it and do it now if it is loose.
Depending on the vintage and quality of the TDs you have, some of the older ones had a a very tight fitment of the piston and cylinder due to the tapers, while laters ones have a relatively sloppy fit and little or no taper. This then means that the tight ones will take over an hour or more of break in while the sloppy ones will be ready after as little as 5 minutes of running. If the piston gets real tight for the last 1/16 to 1/8 inch of travel, at the top of the stroke (glow head removed) it will need a longer break-in. In any case, here is how we broke them in at Cox prior to testing them for peak RPM:
Run the TD .049 on 15% fuel and use a smaller prop, like a 5x3. Keep the glow plug clip on and run it sloppy rich for the first couple tanks full ( about 5 minutes each time) and let it cool between runs. Check that the glow head is tight after it cools. You will notice some greyish-black metal in the oil during the first run, but it shoul go away by the second run. The idea is to keep the engine turning fast but rich, with a smaller prop.
Run several more tanks with the glow clip removed, you will have to slightly lean the needle valve to keep the engine running, but keep it on the rich side. Next, after cool down and torqing the glow head, run it a bit leaner such that it is on the verge of occasionally 2-cycling. The engine should be 4-cycling, but going back and forth between a 2-cycle and 4-cycle. This will begin to build a little heat in the engine. Repeat this 3-4 times for 5 minutes each and then with the engine running, pinch the fuel line to momentarily lean out the engine for full rpm for about 5 seconds, then release the fuel line and let it go rich for about 15 seconds, then repeat. If at anytime during this process the engine begins to sag while you are pinching the line, it's getting tight and is not ready for full RPM, or you just pinched the line too long and it's running out of fuel. If all is well, try leaning the needle valve a little more until it the engine is just barely missing a little and almost on a clean 2-cycle. It should be making a "whee....da-deee......da-deee..." sound. If the engine can hold this setting without sagging, try pinching the line again and see how it runs when lean. Run several more tanks and then try leaning it fully. If it sags, open the needle valve and continue the break in with it set so it just misses as described above.
Once the engine will hold a lean setting without sagging, you are ready to try the full size prop. Bolt on a 6x3 grey and start over with a rich run where its on the verge of breaking into a clean 2-cycle as described above. Pinch the line and note how it holds the lean setting. If it seems fine, try leaning out the needle valve fully on the next run. Loose engines will be ready at this point, but tight engines will require more rich running with a full load( the bigger prop) before they can hold a lean setting. Since no two are alike, you have listen to the engine to determine when it is ready. If the engine will not hold a lean setting and tightens up, go back to the 5x3 and continue break-in at a fast 4-cycle for another 15 minutes. On tighter engines, it is well worth the extra effort, as they will be real power houses once broke in, but if you rush it you will ruin them.
Many times, if the engine is tightening up repeatedly, it may have varnish/shellac in the cylinder and you will have to scour the cylinder wall with #0000 steel wool or a devarnishing brush ( rifle bore brushes work well). Clean the cylinder, lube, and re-assemble the engine and continue the break-in.
Do the same for the .09 TD. The secrets are using a small break-in prop to allow the engine to build RPM, while running rich to avoid a heat seizure, allowing the engine to fully cool between runs (heat cycling) and slowly bringing up the RPM incrementally as the break-in progresses. An extended break-in will not hurt an engine, but you can ruin a tight engine by not breaking it in long enough.
Have fun, good luck!
11-02-2012, 05:10 PM
#7
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RE: Advice for first running of a .049 and .090
ORIGINAL: RickP
What voltage is the glow plug, can I use my variable power panel from my glow stuff?
What voltage is the glow plug, can I use my variable power panel from my glow stuff?
Fun site to poke around: [link=http://www.mh-aerotools.de/airfoils/cox_frameset.htm]Cox historical info and instructions[/link]
11-05-2012, 02:16 PM
#8
RE: Advice for first running of a .049 and .090
Jaymen is spot on for the break in proceedure, especially on a TD or Medallion. I have some TD's and Medallions that are 30 years old and still start easily and run like a top. While the reedies are still available thanks to Bernie, the TD's and Medallions are no longer made. For those a proper break in is well worth the time and will pay off in spades over the years.
11-05-2012, 03:56 PM
#11
RE: Advice for first running of a .049 and .090
Hey Guys, yes that's the plan! However in light of this thread I think I need to break in my engines the "conventional" way first. I'll have enough tuning problems as it is in the fan. Tower doesn't seem to carry props for these guys, and you never know what is in the project pipeline anyway, might be something here ;-)
RP
RP
11-05-2012, 04:05 PM
#12
RE: Advice for first running of a .049 and .090
You can get rubber duckys (Cox 5X3) for break in's from Bernie at http://www.coxengines.ca/
Tower sells the Master Airscrew 7X4's for breaking in the 09's. They also sell the APC 5.7X3 (great prop for the TD) and APC's for the 09's after break in.
Tower sells the Master Airscrew 7X4's for breaking in the 09's. They also sell the APC 5.7X3 (great prop for the TD) and APC's for the 09's after break in.
11-08-2012, 03:33 PM
#13
RE: Advice for first running of a .049 and .090
Okay guys, I ordered all of the hardware (props, engine mounts...) to break these two engines in on the bench. The .049 and the .090. except I only got 25% fuel from sig. I see most of you guys are only using 15%. 25% should be okay no?
Also, what about the fine NV on the .049. 4 1/2 turns out is for the coarse thread NV...
RP
Also, what about the fine NV on the .049. 4 1/2 turns out is for the coarse thread NV...
RP
11-17-2012, 11:51 AM
#16
RE: Advice for first running of a .049 and .090
Thanks for the advice. It took me all day to get set up but I ran three tanks through the motor at a setting where it would barely just stay running, running sloppy rich. The cylinder was still cool to the touch after the first two runs. After the third I turned in the needle a bit to keep it running for the whole tank. I can see this process will take several days - whew a lot of work! Much thanks though!
One question, how can I tell if the rod needs to be reset?
Rick
One question, how can I tell if the rod needs to be reset?
Rick
11-17-2012, 11:57 AM
#17
RE: Advice for first running of a .049 and .090
ORIGINAL: jaymen
Depending on the vintage and quality of the TDs you have, some of the older ones had a a very tight fitment of the piston and cylinder due to the tapers, while laters ones have a relatively sloppy fit and little or no taper. This then means that the tight ones will take over an hour or more of break in while the sloppy ones will be ready after as little as 5 minutes of running. If the piston gets real tight for the last 1/16 to 1/8 inch of travel, at the top of the stroke (glow head removed) it will need a longer break-in.
Depending on the vintage and quality of the TDs you have, some of the older ones had a a very tight fitment of the piston and cylinder due to the tapers, while laters ones have a relatively sloppy fit and little or no taper. This then means that the tight ones will take over an hour or more of break in while the sloppy ones will be ready after as little as 5 minutes of running. If the piston gets real tight for the last 1/16 to 1/8 inch of travel, at the top of the stroke (glow head removed) it will need a longer break-in.
RP
11-19-2012, 05:59 AM
#18
RE: Advice for first running of a .049 and .090
Hey Guys,
Just some comments here - I started with the Tee Dee 090. First I drilled open the pressure port before I started. It really seems to be overkill as it kept flooding with the tank CL on the NV, I am sure once I run it in and get the right NV setting it won't be an issue, but it is complicating things now that is for sure.
I have about 1/2 a quart of 25% sig champion fuel through it. That is 7 runs and I am guessing they are about 3.5 to 4 min in lenght. So that is about 24 min of run time, just about halfway there?
The 6x3 prop is the ticket but it took a beating from my chicken stick as it was a really flimsy prop. It was the only one I had so I think I am going to cut down my 7x4 glass prop and continue with that this afternoon.
I am not sure how many head gasktes should be on the motor. There was only one when I bought it. I put in an extra one to be on the safe side as I think the 049 has three to start.
If you can think of any comments or suggestions please let me know. So far you all have been a great help.
Kind regards,
Rick
Just some comments here - I started with the Tee Dee 090. First I drilled open the pressure port before I started. It really seems to be overkill as it kept flooding with the tank CL on the NV, I am sure once I run it in and get the right NV setting it won't be an issue, but it is complicating things now that is for sure.
I have about 1/2 a quart of 25% sig champion fuel through it. That is 7 runs and I am guessing they are about 3.5 to 4 min in lenght. So that is about 24 min of run time, just about halfway there?
The 6x3 prop is the ticket but it took a beating from my chicken stick as it was a really flimsy prop. It was the only one I had so I think I am going to cut down my 7x4 glass prop and continue with that this afternoon.
I am not sure how many head gasktes should be on the motor. There was only one when I bought it. I put in an extra one to be on the safe side as I think the 049 has three to start.
If you can think of any comments or suggestions please let me know. So far you all have been a great help.
Kind regards,
Rick
11-19-2012, 09:23 AM
#19
RE: Advice for first running of a .049 and .090
The pressure port [plastic nipple] on the side of the engine isn't very reliable. I would plug it back up and use backplate pressure fitting, or else drill and tap one of the engine mounting lugs for a pressure fitting. You will most likely need a fine thread needle valve if the stock .09 NV is as crude as the stock .049 NV.
A OS.10 NVA can be mounted remotely [where ever it is handy] in your pressurized fuel system and these work very well for fine metering of fuel.
As for head gaskets, let the oily exhaust spray blast against a piece of cardboard. If the color is dark brown you on the verge of too much compression for the amount of load [and or nitro%]. Amber color tells you that the compression is a good match for the load and the nitro % you have chosen to run...but always test your limits by going too far [briefly], then back off.
It is a juggling act between Load, Compression & Nitro. It isn't very critical in most cases, but in this case you are trying to get the most power and reliability in an unorthodox application.
A OS.10 NVA can be mounted remotely [where ever it is handy] in your pressurized fuel system and these work very well for fine metering of fuel.
As for head gaskets, let the oily exhaust spray blast against a piece of cardboard. If the color is dark brown you on the verge of too much compression for the amount of load [and or nitro%]. Amber color tells you that the compression is a good match for the load and the nitro % you have chosen to run...but always test your limits by going too far [briefly], then back off.
It is a juggling act between Load, Compression & Nitro. It isn't very critical in most cases, but in this case you are trying to get the most power and reliability in an unorthodox application.
11-19-2012, 02:13 PM
#20
Senior Member
RE: Advice for first running of a .049 and .090
I run my 09s on backplate pressure with a oneway valve in the pressure line. The stock needle works fine. I have one of the KK 09 fine thread needles, but have never used it or seen a real need for it. I don't ordinarily use a chicken stick, but rather a thick leather glove. The trick is to do a prime on the side of the piston, turn the engine over one time only, then turn prop backwards to vertical. Attach battery, and hit the prop forward with your gloved finger. With a little practice this about foolproof. If you get the engine started and it dies, pull the the vent plug to release the tank pressure, else you get the crankcase flooded.
The 049 does need the fine thread needle to run consistently on crankcase pressure.
The 049 does need the fine thread needle to run consistently on crankcase pressure.
11-19-2012, 04:22 PM
#21
RE: Advice for first running of a .049 and .090
Hi Guys,
I got another 22 min or so of run time this afternoon (I must be close to 50 min run time) and I have finished off one qt of fuel. This thing must be getting close to broken in, for one thing it is starting and running backwards better lol. On the last run tonight I let it run through with a lean setting for the entire tank and never sagged or got tight. I guess a few more runs like this and then I can try the 7x4 prop?
Since I am out of 25% nitro can I start burning the 35% I have bought, or should I get more 25%? The exhaust oil is amber so I guess I can also remove one of the head gaskets. Honestly, the nipple port seems to be working really well. I am going to leave it for now. I couldn't find any backplate taps for the 090 which is why I went this way. Tapping the motor mount seems like more work than it is worth.
RP
I got another 22 min or so of run time this afternoon (I must be close to 50 min run time) and I have finished off one qt of fuel. This thing must be getting close to broken in, for one thing it is starting and running backwards better lol. On the last run tonight I let it run through with a lean setting for the entire tank and never sagged or got tight. I guess a few more runs like this and then I can try the 7x4 prop?
Since I am out of 25% nitro can I start burning the 35% I have bought, or should I get more 25%? The exhaust oil is amber so I guess I can also remove one of the head gaskets. Honestly, the nipple port seems to be working really well. I am going to leave it for now. I couldn't find any backplate taps for the 090 which is why I went this way. Tapping the motor mount seems like more work than it is worth.
RP
11-19-2012, 04:53 PM
#22
RE: Advice for first running of a .049 and .090
Why run the 7x4 prop..? No comprendo.
If the exhaust spray is clear of metallic residue and it runs well with the break in prop for a few tanks, then it is time to see how well it runs with the fan.
Aim a fan at the engine as it runs to help simulate inflight conditions.
To answer your earlier question about ball socket maintenance, your goal is to maintain zero slop.
Zero point zero.
If the exhaust spray is clear of metallic residue and it runs well with the break in prop for a few tanks, then it is time to see how well it runs with the fan.
Aim a fan at the engine as it runs to help simulate inflight conditions.
To answer your earlier question about ball socket maintenance, your goal is to maintain zero slop.
Zero point zero.
11-19-2012, 06:40 PM
#23
RE: Advice for first running of a .049 and .090
Well,
I like the sounds of that. I am relying on a lot of your recommendations here, and I thought running a 7x4 prop would finish the break in period. But if I am done that thats good too! I'll run a few more tomorrow just to be sure and then put the fan together (and check the ball socket). Should I wait and get more 25% fuel or just run the 35% I bought?
I'll report when I'm done
Thanks
RP
I like the sounds of that. I am relying on a lot of your recommendations here, and I thought running a 7x4 prop would finish the break in period. But if I am done that thats good too! I'll run a few more tomorrow just to be sure and then put the fan together (and check the ball socket). Should I wait and get more 25% fuel or just run the 35% I bought?
I'll report when I'm done
Thanks
RP
11-19-2012, 07:15 PM
#24
RE: Advice for first running of a .049 and .090
If it isn't blowing plugs and having preignition trouble with the 6x3 prop on 35% nitro...that tells you one thing. It likes 6x3 props with that set up.
There is no way that anyone can say whether or not that fan will present a similar load.
I say this until I'm blue in the face [not here, but in general]..if you aren't sure about running conditions with a high performance application, err on the side of caution.
You will be testing an unknown load [your fan], so I would choose low compression and low nitro to get the ball rolling...with at least 25% straight castor.
Someone else with prior knowledge might chime in with specific information about this same exact set up, but I would at least use the least amount of compression on low nitro at first just to be able to evaluate the exhaust spray and how the plug looks after each run. You have so much invested already in this project.
There is no way that anyone can say whether or not that fan will present a similar load.
I say this until I'm blue in the face [not here, but in general]..if you aren't sure about running conditions with a high performance application, err on the side of caution.
You will be testing an unknown load [your fan], so I would choose low compression and low nitro to get the ball rolling...with at least 25% straight castor.
Someone else with prior knowledge might chime in with specific information about this same exact set up, but I would at least use the least amount of compression on low nitro at first just to be able to evaluate the exhaust spray and how the plug looks after each run. You have so much invested already in this project.
11-20-2012, 11:12 AM
#25
Senior Member
RE: Advice for first running of a .049 and .090
The Aeromodeller review gives peak HP for the TD 09 at 19,000 with 30% nitro fuel. I've flown mine for some years, in CL stunt, with Cox 7 x 3.5 prop, 10% nitro, 20% oil, half and half, Sig Champion fuel. I released at 14,500 to 15,000 depending on wind conditions. I have leaned one to over 17,000 on the bench, but the engine would not hold that RPM with the 10% nitro fuel. I'd suggest you try a lower nitro fuel to start out with. As said, i felt that the engine handled better, though with less power, on the 10% fuel than it did on 25%.
